But as the Washington Post reports, the money didn't actually come directly from Trump. It was donated to the Susan G. Komen organization – the breast cancer non-profit that hosted the fundraiser – by another non-profit: the Donald J. Trump Foundation.

Trump is the president of the foundation, but its money comes primarily from other people. In other words, it looks like Trump gave to charity by taking from charity.

What's more, at the time of the fundraiser, Trump hadn't given any money to the very foundation named after him for three years, according to the Post.

In doing all this, Trump may have violated IRS rules regarding "self-dealing." These are rules that prohibit the officials of non-profits from using their charities for their own benefit.

But what really determines whether or not this was illegal is what Trump did with the memorabilia he purchased. Right now, it's not quite clear what happened to it.

Still, this is hardly the first time Trump – who is currently the presumptive GOP nominee for president – has been embroiled in dubious dealings regarding charity.